Two cycle engine



June 2, 1931. L. 0. FRENCH 1,807,838

TWO-CYCLE ENGINE Filed A ril 27. 1929 Patented June 2, 1931 UNITE STATATENT EOFFE'C" TWO cYcLE ENGINE Application filed April 27,

The invention relates to internal combustion engines and moreparticularly to two cycle engines of the port-scavenging type.

One of the objects of the invention is to provide an exhaust andscavenging port arrangement giving better distribution and more effective purging of the cylinder of the burnt gases over the oppositelydisposed port type by alternating the inlet ports with the exhaust portsand preferably where the piston controlling these ports has asubstantially flat top and the incoming scavenging medium is deflectedupwardly by grooves formed in the piston.

A further important object of the invention is to form the cylinderadjacent the ports in the form of a barrel so that the ports may beaccurately formed in the cylinder by milling or other suitable finishingoperation, the barrel fitting into a supporting cylinder whichcooperates therewith to form the exhaust and intake passageways leadingto the ports. Furthermore, the deflector grooves may be accuratelymachined or finished on the piston and the top finished ofl to theproper height to obtain accurate port registry and overcome thedisadvantages usually encountered in this connection, where accuracy ofcasting the ports or deflectors is relied upon.

The invention further consists in the several features hereinafter setforth and more particularly defined by claims at the conclusion hereof.

In the drawings Fig. l is a vertical sectional View through an internalcombustion engine embodying the invention, parts being broken away;

Fig. 2 is a detail sectional view taken on the line 22 of Fig. 1.

Referring to the drawings the numeral 4 designates the cylinder head, 5the cylinder, 6 the piston working therein, operatively connected bywristpin 7 and connecting-rod 8 to the crank shaft 9 suitably journalledin the crank case 10.

The cylinder 5 is connected to the crank case 10 by a supportingcylinder or casing 11 having a flange 12 connected by bolts 13 to a1929. Serial No. 358,587.

flange 14 on the cylinder and a flange 15 connectedby'bolts 16 to thecrank case.

The cylinder 5 has a jacket space 17 and an annular groove 18cooperating with the casing 11 to form an exhaust gas passageway havingan outlet 19, the bottom wall 20 of said groove seating against ashoulder 21 formed on said casing. The cylinder 5 also has a barrelextension 22 fitting Within the bore of the casing 11 and cooperatingwith recessed portions thereof to form an intake passageway 23 and atransfer passage 24 from the crank case to said passageway.

Either the air charge of a Diesel type engine or the combustible mixturecharge of a carburetor type engine maybe introduced into the crank casethrough a port 25 in the parts 10 and 22 uncovered by the piston at theendof its out stroke, or the usual suction inlet valve, controlling apassage to the crank case, may be'used for this purpose.

2 The exhaust ports 26, establishing communication between theinteriorof the cylin: der 5 and the passage 18, are radially disposedand uncovered by the piston 6 near the end of its power stroke, the topof the piston being flat or substantially plain suraced to permit readyregistry thereof with these ports and also permit of ,close clearancesbetween the piston and head inthe case of high compression engines.

-The scavenge inlet ports 2,7 are formed in the cylinder barrel 22 belowand in the spaces between the exhaust ports to establish communicationbetween the 23 and thecylinder. These ports may be straight but arepreferably upwardly inclined, as shown, and are uncovered by the pistonas it nears the end of its inward stroke after the exhaust ports havebeen uncovered, the incoming scavenging medium being directedupwardlyalongthe cylinder walls by the walls of the grooves 28 formed inthe piston and moving into registry therewith, as shown in the drawings.

Thus the scavenging medium is directed upwardly ina plurality of streamsas the exhaust gases flow outwardly and finally strike the head 5 andare deflected inwardly, mingling witheach other and thus fillingthe upppy passag way per part of the cylinder and driving the exhaust gasesahead of them until the cylinder is well filled with fresh air or a newcharge, the head 5 preferably having inwardly curved walls 29 to assistthe deflection of the streams into the center of the cylinder.

The cylinder head has a threaded passage 30 for the reception of asparlcplug, if an explosive mixture engine, or a fuel injector if an oilengine. With an explosive mixture engine the charge 18 ignited as usualat the end of the compression stroke to produce constant volumecombustion. With a fuel injector or liquid fuel type engine the fuelcharge introduced near the end of the compression stroke is ignited bythe heat of compression or auxiliary ignition devices where lowercompressions are used.

Inasmuch as the ports 26 and 27 are formed in a separable cylinder theymay be readily and accurately machined or hand-finished to accuratelyregister with the top and grooves in the piston and the difliculties ofmisalignment of ports through shifting of cores in casting iseliminated.

I desire it to be understood that this invention is not to be limited toany particular 7 form or arrangement of parts except insofar as suchlimitations are specified in the claims.

What I claim as my invention is:

1. In a two cycle internal combustion engine, the combination of acylinder head, a cylinder, a piston working in said cylinder, saidcylinder having exhaust and scavenge ports formed therein successivelyuncovered of its inner stroke, I

by the piston at the end said exhaust ports radially arranged andalternating with said scavenge ports, said piston having shallow groovesformed therein registering with said scavenge ports to deflect thescavenging medium upwardly along the wall of the cylinder.

2. In a two cycle internal combustion en gine, the combination of acylinder head, a cylinder, a piston working'in said cylinder, saidcylinder having exhaust and scavenge ports formed therein successivelyuncovered by the piston at the end of its inner stroke, said exhaustports being radially arranged and alternating with said scavenge ports,

said piston having shallow grooves formed therein registering with saidscavenge ports to deflect the scavenging medium upwardly along the wallof the cylinder, said cylinder head having inwardly curved walls todeflect the streams of said scavenging medium toward the center of thecylinder and downwardly. I

3. In a two cycle internal combustion engine, the combination of acylinder head, a cylinder, a piston working in said cylinder, saidcylinder having exhaust and scavenge ports formed therein successivelyuncovered by the piston at the end of its inner stroke, said ports beingradially arranged and alter-

